The subject matter described herein relates generally to methods and systems for operating wind turbines, and more particularly, to methods and systems for reducing vibrations in wind turbines which are erected in a body of water.
At least some known wind turbines include a tower and a nacelle mounted on the tower. A rotor is rotatably mounted to the nacelle and is coupled to a generator by a shaft. A plurality of blades extend from the rotor. The blades are oriented such that wind passing over the blades turns the rotor and rotates the shaft, thereby driving the generator to generate electricity.
In the past, wind turbines have often be installed onshore allowing for well-known construction methods and also easy accessibility and maintenance. However, availability of onshore sites becomes rare in some countries. Furthermore, environmental impact of onshore wind turbines on residents living near the turbine site impose, e.g., size limitations onto onshore turbines. For these and other reasons, offshore wind turbine sites, i.e. sites which are located in a body of water, are attracting more and more interest during recent years. However, offshore wind turbines encounter specific challenges not experienced with onshore wind turbines that pose technical and logistical problems still to be solved. Some of these problems are related to the interaction between an offshore wind turbine and the body of water surrounding it.